This invention relates to novel polymeric insecticidal compositions with improved, longer-lasting, insecticidal properties. It also relates to a method for retarding the migration of insecticides which have been incorporated into polymeric articles. This invention further relates to a method for protecting certain crops from insect damage by application of polymeric articles prepared by the method of the present invention.
In known procedures for protecting fruits and vegetables from insect damage, insecticides are sprayed multiple times on the fruits or vegetables during the growing season. Such procedures have the disadvantage of adding pesticides to the environment which do not reach the targeted fruit or vegetable crop. Further, the persons applying the spray are exposed to the non-target pesticide spray. With particular crops, such as date palms where the fruit can be as high as 25 feet or more above the ground, the difficulty of isolating the persons applying the spray from the non-target spray is even more difficult due to the need to use high pressure spraying equipment. To overcome these disadvantages, insecticides have been incorporated into polymeric articles, which in turn are applied to the crops or in the vicinity thereof, thus reducing exposure of both the environment and the applicator to unnecessary quantities of active ingredients.
In methods where O-halopyridyl phosphate-containing polymer films are employed, such films suffer the problem of having the insecticide migrate too quickly from the film. Migration is defined to mean that the insecticide moves or diffuses to the surface of the polymer film where it is volatilized. This rapid migration of the O-halopyridyl phosphate insecticide decreases the concentration of insecticide present in the polymer, thus reducing the effectiveness of shrouds, bags or film produced therefrom for controlling insects.